SARS-CoV-2 Variants,South Sudan,January–March 2021

As the coronavirus pandemic continues, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequence data are required to inform vaccine efforts. We provide SARS-CoV-2 sequence data from South Sudan and document the dominance of SARS-CoV-2 lineage B.1.525 (Eta variant) during the country''s second wave of infection.     

Influence of neurotrophins on the synaptogenesis of inner hair cells in the deaf Bronx waltzer (bv) mouse organ of Corti in culture

The Bronx waltzer (bv) deaf mouse is characterized by massive degeneration of the primary auditory receptors, the inner hair cells, which occurs during the time of expected afferent synaptogenesis. The process is associated with degeneration and protracted division of the normally postmitotic afferent spiral ganglion neurons. To investigate the potential role of neurotrophins in the afferent synaptogenesis of inner hair cells, we exposed bv newborn cochleas in organotypic culture to brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and nerve growth factor (NGF), and also to gamma aminobutyric acid (GABA), for up to 8 days. The study was done using light and electron microscopy. Only about 20% of the inner hair cells survived in culture, regardless of the treatment, similar to the number in the intact mutant in our colony. Depending on the exogenous treatment, this population consisted of either innervated ultrastructurally normal cells or denervated dedifferentiated cells wrapped-in lieu of nerve endings-by the supporting inner phalangeal and border cells. In the control and GABA cultures, inner hair cells were mostly denervated. BDNF and NT-3 alone or combined increased synaptogenesis and hair cell survival only during the first 3 days (by about 10%); however, the cells became denervated by 8 postnatal (PN). Only NGF induced stable innervation and differentiation of neurosensory relationships, including supernumerary innervation characteristic of the intact bv. Denervation among the remaining 20% of inner hair cells induced a reactive wrapping by inner phalangeal and border cells which evidently extended inner hair cell survival. Immunocytochemical studies of these reactive supporting cells were done in the intact (8 PN) mutant cochlea. The supporting cells that provide sustenance to the denervated inner hair cells displayed strong BDNF (and possibly NT-3) immunoreactivity. Subsequently, we revealed the presence of all three neurotrophins in the inner hair cell region of the developing (1-8 PN) cochlea of the normal ICR mouse. The inner hair cells expressed all three neurotrophins; BDNF prevailed in the inner phalangeal cells, NT-3 in the pillar cells and inner phalangeal cells, and NGF in the pillar cells. In conclusion: initially, the 80% loss of inner hair cells is apparently caused by their failed afferent synaptogenesis. Exogenous neurotrophins influence synaptogenesis in the bv in culture, but NGF alone is successful in promoting stable neurosensory relationships. The presence of neurotrophins in supporting cells in the normal and degenerating cochlea indicates their role in the sustenance of inner hair cells.     

Impact of laparoscopic right hemicolectomy for colon cancer

INTRODUCTION

This study specifically examined right colonic cancer resection, a common operation for colorectal surgeons starting laparoscopic resection, to assess the impact of commencing laparoscopy.

PATIENTS AND METHODS

A total of 56 patients undergoing open (n = 34) and attempted laparoscopic (n = 22) elective right hemicolectomy for colorectal cancer between November 2003 and March 2007 were compared. Postoperative stay was the primary outcome. Secondary outcomes included analgesic requirements, bowel recovery, morbidity and mortality. Frequency of laparoscopic versus open surgery over time was also examined.

RESULTS

Resections attempted laparoscopically increased from 9.1% to 75% in the first and last quarters of the study period, respectively (P = 0.0002). Uptake of ‘enhanced recovery’ was mainly in the laparoscopic group. Conversion was required in two of 22 patients. Attempted laparoscopic cases had a shorter median postoperative stay (6 vs 10 days; P < 0.0001), duration of parenteral or epidural analgesia (48 vs 72 h; P < 0.0001) and time to first bowel action (3 vs 4 days; P = 0.001) compared with open cases. Demography, tumour characteristics, morbidity and mortality were comparable between groups. Multivariate analysis identified decreased age, attempted laparoscopic surgery, use of enhanced recovery and absence of complications as independently shortening postoperative stay.

CONCLUSIONS

Advantages of laparoscopic surgery and enhanced recovery, even early in a surgeon''s experience, suggest this is the preferred mode for elective right colon cancer resection.     

Robot-assisted pancreatic surgery: a systematic review of the literature

Background

To potentially improve outcomes in pancreatic resection, robot-assisted pancreatic surgery has been introduced. This technique has possible advantages over laparoscopic surgery, such as its affordance of three-dimensional vision and increased freedom of movement of instruments. A systematic review was performed to assess the safety and feasibility of robot-assisted pancreatic surgery.

Methods

The literature published up to 30 September 2011 was systematically reviewed, with no restrictions on publication date. Studies reporting on over five patients were included. Animal studies, studies not reporting morbidity and mortality, review articles and conference abstracts were excluded. Data were extracted and weighted means were calculated.

Results

A total of 499 studies were screened, after which eight cohort studies reporting on a total of 251 patients undergoing robot-assisted pancreatic surgery were retained for analysis. Weighted mean operation time was 404 ± 102 min (510 ± 107 min for pancreatoduodenectomy only). The rate of conversion was 11.0% (16.4% for pancreatoduodenectomy only). Overall morbidity was 30.7% (n = 77), most frequently involving pancreatic fistulae (n = 46). Mortality was 1.6%. Negative surgical margins were obtained in 92.9% of patients. The rate of spleen preservation in distal pancreatectomy was 87.1%.

Conclusions

Robot-assisted pancreatic surgery seems to be safe and feasible in selected patients and, in left-sided resections, may increase the rate of spleen preservation. Randomized studies should compare the respective outcomes of robot-assisted, laparoscopic and open pancreatic surgery.     

Analysis of clonal expansions through the normal and premalignant human breast epithelium reveals the presence of luminal stem cells

It is widely accepted that the cell of origin of breast cancer is the adult mammary epithelial stem cell; however, demonstrating the presence and location of tissue stem cells in the human breast has proved difficult. Furthermore, we do not know the clonal architecture of the normal and premalignant mammary epithelium or its cellular hierarchy. Here, we use deficiency in the mitochondrial enzyme cytochrome c oxidase (CCO), typically caused by somatic mutations in the mitochondrial genome, as a means to perform lineage tracing in the human mammary epithelium. PCR sequencing of laser‐capture microdissected cells in combination with immunohistochemistry for markers of lineage differentiation was performed to determine the clonal nature of the mammary epithelium. We have shown that in the normal human breast, clonal expansions (defined here by areas of CCO deficiency) are typically uncommon and of limited size, but can occur at any site within the adult mammary epithelium. The presence of a stem cell population was shown by demonstrating multi‐lineage differentiation within CCO‐deficient areas. Interestingly, we observed infrequent CCO deficiency that was restricted to luminal cells, suggesting that niche succession, and by inference stem cell location, is located within the luminal layer. CCO‐deficient areas appeared large within areas of ductal carcinoma in situ, suggesting that the rate of clonal expansion was altered in the premalignant lesion. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Hypoxic hepatitis in children after cardiac surgery

<正>To the Editor: Hypoxic hepatitis(HH), also known as ischemic hepatitis or shock liver, is a liver injury characterized by necrosis of centrilobular hepatocytes with a rapid increase in serum aminotransferase levels. The incidence rate of HH among patients in the intensive care unit(ICU) was found to be 0.9%-11.9% [1]. Occurrence of HH appears to have a significant impact on the clinical outcome.